I haven't seen either.
For some reason though I imagine an aurora would be more inspiring but it'd have to be a proper overhead display and not just a faint glow in the distance.
Lava is another one I want to see too, we nearly went to Etna and Stromboli for the Venus transit but decided on Crete and Santorini instead. Technically Santorini is still geo active but there is no lava there.